U.S. patent application number 12/718862 was filed with the patent office on 2011-09-08 for low frequency diversity antenna system.
This patent application is currently assigned to RESEARCH IN MOTION LIMITED. Invention is credited to QINJIANG RAO.
Application Number | 20110215971 12/718862 |
Document ID | / |
Family ID | 44530880 |
Filed Date | 2011-09-08 |
United States Patent
Application |
20110215971 |
Kind Code |
A1 |
RAO; QINJIANG |
September 8, 2011 |
LOW FREQUENCY DIVERSITY ANTENNA SYSTEM
Abstract
A diversity antenna system that operates within a low frequency
band ranging from 700 Megahertz is disclosed. A plurality of
antennas are folded onto a single printed circuit in a meander
pattern configuration. Each antenna has an independent feed port
and ground pin. The plurality of antennas are configured within a
compact mobile phone space to produce a high isolation and low
correlation at resonating frequencies within the 700 Megahertz
frequency band.
Inventors: |
RAO; QINJIANG; (WATERLOO,
CA) |
Assignee: |
RESEARCH IN MOTION LIMITED
WATERLOO
CA
|
Family ID: |
44530880 |
Appl. No.: |
12/718862 |
Filed: |
March 5, 2010 |
Current U.S.
Class: |
343/702 ;
343/700MS; 343/893 |
Current CPC
Class: |
H01Q 1/243 20130101;
H01Q 1/521 20130101; H01Q 21/28 20130101; H01Q 9/0421 20130101 |
Class at
Publication: |
343/702 ;
343/893; 343/700.MS |
International
Class: |
H01Q 9/04 20060101
H01Q009/04; H01Q 1/24 20060101 H01Q001/24; H01Q 21/00 20060101
H01Q021/00 |
Claims
1. A mobile communication device comprising: a plurality of
antennas coupled to a single planar dielectric substrate, each
antenna comprising a plurality of radiating conductive strips
configured in a meander pattern, wherein a first antenna of the
plurality of antennas is disposed at a first corner of the
dielectric substrate; a second antenna of the plurality of antennas
is disposed at a second corner of the dielectric substrate opposite
the first corner, and a third antenna of the plurality of antennas
is disposed at a corner opposite the first antenna and diagonal
with respect to the position of the second antenna; a plurality of
feed ports, wherein a first feed port is coupled to the first
antenna, a second feed port is coupled to the second antenna, and a
third feed port is coupled to the third antenna; and a plurality of
ground pins, wherein a first ground pin is coupled to the first
antenna and positioned in a vertical coordinate direction with
respect to the first feed port; a second ground pin is coupled to
the second antenna and positioned in a horizontal coordinate
direction with respect to the second feed port, and a third ground
pin is coupled to the third antenna and positioned in a horizontal
coordinate direction with respect to the second feed port.
2. The mobile communication device of claim 1, further comprising a
ground plane, wherein each ground pin of the plurality of ground
pins are attached to the ground plane.
3. The mobile communication device of claim 1, wherein the
plurality of antennas comprise planar inverted F antennas.
4. The mobile communication device of claim 2, wherein the first
antenna is vertically polarized and the second antenna is
horizontally polarized.
5. The mobile communication device of claim 2, wherein a number of
antennas of the plurality of antennas radiate at a same time within
a range of frequencies in a 700 Megahertz frequency band.
6. The mobile communication device of claim 2, wherein the
plurality of folded antennas are configured to form a plurality of
electrically connected slots that are bent.
7. The mobile communication device of claim 5, wherein the range of
frequencies within the 700 MHz frequency band is from 746 Megahertz
to 787 Megahertz.
8. The mobile communication device of claim 1, wherein the first
antenna and the second antenna of the plurality of antennas are
configured to resonate at a first frequency; and wherein the third
antenna of the plurality of antennas resonate at a second
frequency.
9. An antenna arrangement for a mobile communication device,
comprising: a plurality of antennas, each antenna configured in a
meander pattern with a plurality of radiating conductive strips
folded onto a single planar dielectric; and a plurality of feed
ports, each feed port dedicated to exciting a single antenna of the
plurality of antennas, wherein a number of antennas of the
plurality of antennas radiate at a same time within a range of low
frequencies.
10. The antenna arrangement of claim 9, wherein a first antenna of
the plurality of antennas is disposed at a first corner of the
dielectric substrate; a second antenna of the plurality of antennas
is disposed at a second corner of the dielectric substrate opposite
the first corner, and a third antenna of the plurality of antennas
is disposed at a corner opposite the first antenna and diagonal
with respect to the position of the second antenna.
11. The antenna arrangement of claim 9, further comprising a
plurality of ground pins, wherein a first ground pin is coupled to
the first antenna and positioned in a vertical coordinate direction
with respect to the first feed port; a second ground pin is coupled
to the second antenna and positioned in a horizontal coordinate
direction with respect to the second feed port, and a third ground
pin is coupled to the third antenna and positioned in a horizontal
coordinate direction with respect to the second feed port.
12. The antenna arrangement of claim 9, further comprising a ground
plane, wherein each ground pin of the plurality of ground pins are
attached to the ground plane.
13. The antenna arrangement of claim 9, wherein an electrical
length of each antenna is one-quarter of a wavelength.
14. The antenna arrangement of claim 9, wherein the plurality of
folded antennas is configured to form a plurality of electrically
connected slots that are bent.
15. The antenna arrangement of claim 9, wherein the range of low
frequencies is within a 700 Megahertz frequency band.
16. A communication network comprising: a plurality of antenna
arrangements, each antenna arrangement comprising a plurality of
radiating conductive strips configured in a meander pattern,
wherein a first antenna in an antenna arrangement of the plurality
of antenna arrangements is disposed at a first corner of the
dielectric substrate; a second antenna of the plurality of antennas
is disposed at a second corner of the dielectric substrate opposite
the first corner, and a third antenna of the plurality of antennas
is disposed at a corner opposite the first antenna and diagonal
with respect to the position of the second antenna; a plurality of
feed ports, wherein a first feed port is coupled to the first
antenna, a second feed port is coupled to a second antenna, and a
third feed port is coupled to a third antenna; and a plurality of
ground pins, wherein a first ground pin is coupled to the first
antenna and positioned in a vertical direction with respect to the
first feed port; a second ground pin is coupled to a second antenna
and positioned in a horizontal direction with respect to the second
feed port, and a third ground pin is coupled to a third antenna and
positioned in a horizontal direction with respect to the second
feed port.
17. The communication network of claim 16, wherein the plurality of
antenna arrangements comprise planar inverted F antennas.
18. The communication network of claim 16, wherein an electrical
length of each antenna in the plurality of antenna arrangements is
one-quarter of a wavelength.
19. The communication network of claim 16, wherein a number of
antennas in the antenna arrangement radiate at a same time within a
range of frequencies in a 700 Megahertz frequency band.
20. The communication network of claim 16, wherein said first
antenna and said second antenna of said plurality of antenna
arrangements are configured to resonate at a first frequency; and
wherein the third antenna of said plurality of antenna arrangements
resonate at a second frequency.
Description
BACKGROUND
[0001] 1. Technical Field
[0002] This disclosure relates to a diversity antenna arrangement
for a mobile terminal and more specifically to the design and
implementation of a diversity antenna system that operates within a
fundamental resonant low frequency band of 700 Megahertz (MHz).
[0003] 2. Description of the Related Art
[0004] The design and implementation of multiple antennas with
independent transmit and receive paths on a mobile terminal
introduces significant design challenges for compact devices that
operate in a low frequency range. The Long Term Evolution frequency
spectrum or range supports a number of frequency bands, including a
746-787 MHz band, 882-960 MHz band, 1710-2155 MHz band, and
2500-2700 MHz frequency band. In the low frequency bands, such as
frequency bands, the design of multiple antennas on a mobile
terminal, such as, the 746-787 MHz band mobile cellular handsets,
smart phone's, hand-held computers, and other such devices known to
one skilled in the art, require design considerations to facilitate
and improve antenna isolation and reduce antenna correlation. The
efficiency of an antenna system with multiple antennas is increased
by greater isolation and lower correlation between the antenna
elements. It is typically a challenge to achieve low correlation
and high isolation in mobile terminals of compact size and limited
internal space for components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] For a better understanding of the disclosure and the various
embodiments described herein, reference is now made to the
following brief description, taken in connection with the
accompanying drawings and detailed description, which show at least
one exemplary embodiment.
[0006] FIG. 1 illustrates an isometric planar view of an antenna
diversity system in accordance with an embodiment of the
disclosure;
[0007] FIG. 2 illustrates oblique side views in FIG. 2A and FIG. 2B
of an antenna arrangement in the diversity antenna system
illustrated in FIG. 1 in accordance with an embodiment of the
disclosure;
[0008] FIG. 3 illustrates a plot of measured return loss at
selected operating frequencies of Long Term Evolution frequency
bands for the multiple antenna arrays system illustrated in FIG. 1
according to an embodiment of the disclosure;
[0009] FIG. 4 illustrates a three-dimensional view of the measured
radiation pattern from ports on the antenna diversity system
illustrated in FIG. 1 at a frequency about of 750 MHz according to
an embodiment of the current disclosure;
[0010] FIG. 5 illustrates a plot of the antenna efficiency measured
at a port of the antenna array system illustrated in FIG. 1
according to an embodiment of the current disclosure;
[0011] FIG. 6 is a block diagram of mobile terminal that may
implement illustrative embodiments of the disclosure; and
[0012] FIG. 7 illustrates a communications system implementing the
diversity antenna array system of FIG. 1 according to an embodiment
of the disclosure.
DETAILED DESCRIPTION
[0013] It should be understood at the outset that although an
illustrative implementation of one or more embodiments are provided
below, the description is not to be considered as limiting the
scope of the embodiments described herein. The disclosure may be
implemented using any number of techniques, whether currently known
or in existence. The disclosure should in no way be limited to the
illustrative implementations, drawings, and techniques illustrated
and described herein, which may be modified within the scope of the
appended claims along with a full scope of equivalence. It should
be appreciated that for simplicity and clarity of illustration,
where considered appropriate, the reference numerals may be
repeated among the figures to indicate corresponding or analogous
elements.
[0014] According to an illustrative embodiment, a mobile
communication device comprises a plurality of antennas coupled to a
single planar dielectric substrate. Each antenna comprises a
plurality of radiating conductive strips configured in a meander
pattern. A first antenna of the plurality of antennas is disposed
at a first corner of the dielectric substrate; a second antenna of
the plurality of antennas is disposed at a second corner of the
dielectric substrate opposite the first corner, and a third antenna
of the plurality of antennas is disposed at a corner opposite the
first antenna and diagonal with respect to the position of the
second antenna. The mobile communication device also comprises a
plurality of feed ports. A first feed port is coupled to the first
antenna, a second feed port is coupled to the second antenna, and a
third feed port is coupled to the third antenna. The mobile
communication device also comprises a plurality of ground pins,
wherein a first ground pin is coupled to the first antenna and
positioned in a vertical coordinate direction with respect to the
first feed port, a second ground pin is coupled to the second
antenna and positioned in a horizontal coordinate direction with
respect to the second feed port, and a third ground pin is coupled
to the third antenna and positioned in a horizontal coordinate
direction with respect to the second feed port.
[0015] In accordance with another embodiment of the disclosure, an
antenna arrangement for a mobile communication device comprises a
plurality of antennas, each antenna being configured in a meander
pattern with a plurality of radiating conductive strips folded onto
a single planar dielectric; a plurality of feed ports, wherein each
feed port is dedicated to exciting a single antenna of the
plurality of antennas, wherein a number of antennas radiate at a
same time within a range of low frequencies.
[0016] In accordance with a further embodiment of the disclosure, a
communication network comprising a plurality of antenna
arrangements is disclosed. Each antenna arrangement comprises a
plurality of radiating conductive strips configured in a meander
pattern, a plurality of feed ports and a plurality of ground pins.
A first antenna in an antenna arrangement of the plurality of
antenna arrangements is disposed at a first corner of the
dielectric substrate; a second antenna of the plurality of antennas
is disposed at a second corner of the dielectric substrate opposite
the first corner, and a third antenna of the plurality of antennas
is disposed at a corner opposite the first antenna and diagonal
with respect to the position of the second antenna. A first feed
port of the plurality of feed ports is coupled to the first
antenna, a second feed port is coupled to a second antenna, and a
third feed port is coupled to a third antenna. A first ground pin
of the plurality of ground pins, is coupled to the first antenna
and positioned in a vertical direction with respect to the first
feed port; a second ground pin is coupled to a second antenna and
positioned in a horizontal direction with respect to the second
feed port, and a third ground pin is coupled to a third antenna and
positioned in a horizontal direction with respect to the second
feed port.
[0017] The present disclosure provides a plurality of antennas
arranged on a single printed circuit board and configured for
operation in a mobile communication device within a low frequency
band, and particularly within the 700 MHz frequency band. The
electrical length of each antenna is sized to around a quarter of a
wavelength. The radiation elements of each antenna comprise strips
of conducting material that are folded onto or coupled to a
dielectric to reduce the size of the antenna and enable a number of
antennas to fit within a space commonly provided by a mobile
communication device. As used herein, a first component "coupled
to" a second component means that there are no additional
components present between the first component and the second
component.
[0018] In embodiments of this disclosure, the radiation elements
may lie in or be located in the same plane that contains the feed
port of the radiation elements. The plane may run in an X direction
and Y direction according to a rectangular coordinate or Cartesian
system. In other embodiments, a radiation element may lie in a
planar direction that is different from the plane that contains the
feed port of the radiation element. For example, the radiation
element may run in Z direction, according to a rectangular
coordinate system, that may be symmetric about the plane that
contains the feed port.
[0019] Each antenna includes a feed port that may operate
simultaneously or approximately at a same time, and independently.
The radiation elements of each antenna are laid out in a meander
pattern. The meander pattern may be bent into shapes that form a
number of slots. The layout of each antenna may be arranged or
oriented in orthogonal directions to enable polarization diversity
and reduce coupling between the antennas during operation.
[0020] In illustrative embodiments of this disclosure, the
plurality of antennas may include a number of antennas that operate
to receive and transmit radio frequency signals. For example, in an
illustrative embodiment that comprises two antennas, one antenna
may operate as a receiver and one antenna may operate as a
transmitter. In an illustrative embodiment that comprises three
antennas, two antennas may operate as receivers and one antenna may
operate as a transmitter. The antennas may operate simultaneously
or separately depending on implementation. As used within this
disclosure, "a number of" refers to one or more items.
[0021] Turning now to FIG. 1, an isometric planar view of an
antenna diversity system 100 is depicted in accordance with an
illustrative embodiment of the disclosure. Antenna diversity system
100 includes an arrangement of a plurality of antennas mounted on a
dielectric substrate 104. Antenna arrangement 102 is disposed or
located within a housing 150 for a mobile communication device or
mobile terminal. In the depicted embodiment, dielectric substrate
104 supports a first antenna 110, second antenna 120, and third
antenna 130. First antenna 110, second antenna 120, and third
antenna 130 are connected to independent feed ports and may
individually resonate in separate frequency bands. It must be noted
that the number of antennas arranged and illustrated on dielectric
substrate 104 is not limited to the number or arrangement depicted
in antenna arrangement 102.
[0022] Each antenna is supported by dielectric substrate 104 and
includes a separate feed port and ground pin. The antennas may
include, but are in no way limited to, a planar inverted F antenna
(PIFA), an inverted F antenna (IFA), a type of monopole antenna, a
type of electrical dipole element, such as an isolated magnetic
dipole antenna, or other such antenna elements known to one skilled
in the art.
[0023] Each antenna connected to dielectric substrate 104 includes
a ground or shorting pin connection and an independent feed port.
In the depicted example, first antenna 110 includes first ground
pin 112 and first feed port 114. Second antenna 120 element
includes second ground pin 122 and second feed port 124. Third
antenna 130 includes third ground pin 132 and third feed port 134.
First ground pin 112, second ground pin 122, and third ground pin
132 connect to ground plane 140. First feed port 114, second feed
port 124, and third feed port 134 may connect to each respective
antenna elements, first antenna 110, second antenna 120, and third
antenna 130 through openings or slots in ground plane 140. As
illustrated in FIG. 1, the arrangements of the feed ports and the
ground pins are not meant to imply any physical or architectural
limitations to the manner in which different advantageous
embodiments may be implemented. Other arrangements are possible as
would be recognized by one skilled in the art.
[0024] Ground plane 140 is planar and parallel to dielectric
substrate 104. The antenna elements, first antenna 110, second
antenna 120, and third antenna 130 may be mounted to outer and side
surfaces of dielectric substrate 104. First antenna 110, second
antenna 120, and third antenna 130 may each be positioned
substantially at, around, or near an edge of a dielectric substrate
that is polygonal in shape. In a preferred embodiment, the
polygonal shaped dielectric substrate may be rectangular. In
another embodiment, the polygonal shaped dielectric substrate may
be square.
[0025] Dielectric substrate 104 may be formed from a material that
includes, but is in no way limited to, air, fiberglass, plastic,
and ceramic. In an illustrative embodiment, ground plane 140 may be
embedded in dielectric substrate 104. In another illustrative
embodiment, ground plane 140 may be located under the dielectric
substrate 104. In yet another embodiment, ground plane 140 may be
disposed at a certain height from dielectric substrate 104, as
depicted in the illustrative embodiment of FIG. 1.
[0026] The antenna elements of antenna arrangement 102 may have
dual polarizations or polarization in both an X direction,
Y-direction, and Z direction. For example, first antenna 110 is
polarized in a Y linear direction based on the orientation of first
feed port 114 with respect to first ground pin 112. First feed port
114 and first ground pin 112 are oriented at a ninety degree angle
with respect to each other. Second antenna 120 is polarized in an X
linear direction based on the orientation of second feed port 124
with respect to second ground pin 122 antenna. Second feed port 124
and second ground pin 122 are oriented at a one hundred eighty
degree angle with respect to each other. Third antenna 130 is
polarized in a Y linear direction based on the orientation of third
feed port 134 with respect to third ground pin 132. Third feed port
134 and first ground pin 132 are oriented at a ninety degree angle
with respect to each other. In an embodiment, there may also be
polarization in a Z direction.
[0027] In an illustrative embodiment, third antenna 130 may be
positioned at an opposite edge and substantially within the same
plane of dielectric substrate 104 at a distance that is diagonally
across from or at approximately a forty-five degree angle from the
location of second antenna 120. First antenna 110 and second
antenna 120 may be located across from each other at opposite edges
and substantially within the same plane of the dielectric substrate
104 at approximately ninety degree angles within the plane of the
antenna elements.
[0028] Turning now to FIG. 2, oblique side views including FIG. 2A
and FIG. 2B of antenna arrangement 200 is depicted in accordance
with an illustrative embodiment of the disclosure. In the depicted
examples of FIG. 2, antenna arrangement 200 represent oblique side
views of an implementation of antenna arrangement 102 in FIG.
1.
[0029] Referring first to FIG. 2A, antenna arrangement 200 is an
arrangement that includes first antenna 210, second antenna 220,
and third antenna 230 mounted on a type of support such as a
dielectric substrate 204, printed circuit board or other type of
mounting object known to one skilled in the art. In the
illustrative embodiment, antenna arrangement 200 is a planar
arrangement. In an embodiment, dielectric substrate 204 may be may
be positioned on or over an opposing surface of ground plane 240.
In another embodiment, dielectric substrate 204 may include a
ground plane 240 embedded within.
[0030] First antenna 210 comprises a plurality of conductive strips
210s that may be connected together through soldering or other
attachment means known to one skilled in the art. Conductive strips
210s may vary in width and length and may be formed from a type of
metal such as copper, or other elements know in the art for good
conducting properties. The interconnecting electrically conductive
strips 210s are electrically connected to each other to form
various patterns on the outer surface of dielectric substrate 204.
In an embodiment, the conductive strips 210s may be bent into a
meander pattern. A meander pattern is a loop pattern that may be
configured or bent to form a variety of different shapes. The
meander pattern may be configured to form a number of slots within
the antenna.
[0031] First antenna 210 includes first ground pin 212 and first
feed port 214 oriented in a substantially ninety degree angle from
each other. Additionally the conductive strips are laid out and
connected together in a substantially vertical or Y planar or
linear direction. The orientation of the feed ports and the layout
of the interconnecting microstrip elements of antenna 210 produce a
polarization in the Y direction.
[0032] Second antenna 220 comprises a plurality of conductive
strips 220s that are electrically interconnected through soldering
or other attachment means known to one skilled in the art. Similar
to first antenna 210, the interconnecting conductive strips 220s
may be formed from a conducting metal that has good conducting
properties known to those skilled in the art. The interconnecting
electrically conductive strips 220s are electrically connected to
each other to form various patterns on outer surface of dielectric
substrate 204. In an embodiment, the conductive strips 220s may be
bent into a meander pattern which may include a number of
slots.
[0033] Second antenna 220 includes second ground pin 222 and second
feed port 224 oriented in a substantially one hundred and eighty
degree angle from each other. Additionally the conductive strips
are laid out and connected together in a substantially horizontal
or X planar linear direction. Second feed port 224 is independent
from first feed port 214. The orientation of the feed ports and the
layout of the interconnecting microstrip elements of antenna 220
produce a polarization in the X direction.
[0034] Third antenna 230 includes third ground pin 232 and third
feed port 234 oriented in a substantially ninety degree angle from
each other. Third feed port 234 is independent from all other feed
ports; first feed port 214 and second feed port 224 on antenna
arrangement 200. The orientation of the feed ports and the layout
of the interconnecting microstrip elements of antenna 230 produce a
polarization in the Y direction.
[0035] Additionally, similar to first antenna 210 and second
antenna 220, the conductive strips are laid out and connected
together in a substantially vertical or Y planar or linear
direction. Third antenna 230 comprises a plurality of conductive
strips 230s. The interconnecting electrically conductive strips
230s are electrically connected to each other to form various
patterns on outer surface of dielectric substrate 204. In an
embodiment, the conductive strips 230s may form a meander pattern
on the surface of dielectric 204 and extend along and over the edge
of a number of sides of dielectric 204. The meander pattern 230 may
also include a number of slots.
[0036] In an illustrative embodiment, first antenna 210, second
antenna 220, and third antenna 230 may be selectively configured
for transmitting or receiving simultaneously or separately. For
example, in one illustrative antenna diversity system, first
antenna 210 and second antenna 220 may be paired as receiving
antennas to cover or handle uplink transmissions while third
antenna 230 operates as a transmitting antenna to handle downlink
transmissions. Uplink transmissions are radio frequency
transmissions from user equipment to a base station. Downlink
transmissions are radio frequency transmissions from a base station
to user equipment.
[0037] The illustration of antenna arrangement 200 in FIG. 2 is not
meant to imply physical or architectural limitations to the manner
in which different advantageous embodiments may be implemented. For
example, in an advantageous embodiment, the antenna arrangement may
include two antennas with a first antenna configured to operate on
uplink transmission and a second antenna configured to operate on
downlink transmissions.
[0038] In another advantageous embodiment, more than three antennas
may be arranged on a single dielectric substrate. In yet another
advantageous embodiment, an antenna arrangement may be configured
with a plurality of antennas from which two or more may be selected
for receiving and transmitting radio frequency signals. A spatial
distance of at least 200 mm is required in order to achieve high
isolation and reduce coupling between the first antenna and second
antenna.
[0039] In the illustrative embodiment of antenna arrangement 200 of
FIG. 2, although the distance between the antenna elements, such as
first antenna 210 and second antenna 220, may be less that 200 mm,
the orientation of the feed ports and ground pins result in
polarization in orthogonal or opposing linear X and Y directions,
that enables good isolation between the first antenna 210 and
second antenna 220. The orthogonal polarization results in a
polarization diversity that reduces signal fading within a system.
Additionally, the spatial distance between second antenna 220 and
third antenna 230 may be positioned at a diagonal distance on
dielectric substrate 240. A diagonal distance is the largest
possible spacing that may exist between antennas in a same plane.
Second antenna 220 includes a feed port and ground pin that enable
polarization in a linear X direction. Third antenna 230 includes a
feed port and ground pin that enables polarization in a linear Y
direction. The opposite or orthogonal linear polarization enables
good isolation between second antenna 220 and third antenna
230.
[0040] Referring next to oblique side view FIG. 2B, an oblique
partial side view of antenna arrangement 200 from a second
perspective that illustrates the configuration of third antenna 230
is illustrated. FIG. 2B also illustrates an exemplary current
distribution of antenna arrangement 200 at a specific point in
time.
[0041] The current distribution of antenna arrangement 200 may
change based on a specified frequency of operation. At a distance
of about one-half lambda,
.lamda. 2 , ##EQU00001##
the direction of current Bow at a particular instance in time may
change to a direction that is the reverse of the direction at the
particular instance. In an embodiment of this disclosure, the
electrical length of each antenna element, such as third antenna
230, is approximately one-quarter lambda,
.lamda. 4 , ##EQU00002##
in length, where lambda is the wavelength of the operating
frequency. The electrical length of the antenna elements fixes the
distribution of current and current flow in a specific direction
since the electrical length of each antenna element in antenna
arrangement 200 is less than
.lamda. 2 . ##EQU00003##
[0042] Third antenna 230 has a meander pattern that extends along
an X direction, a Y direction, and a Z direction. Third antenna 230
includes third ground pin 232 and third feed port 234. Third ground
pin 232 is oriented or laid out at a ninety degree angle in a
linear Y direction from third feed port 234. Third antenna 230 is
comprised of conductive strips in a meander pattern that is
disposed on and about dielectric substrate 204. The orientation of
second feed port 234 with respect to third ground pin 132 and the
layout of the interconnecting conductive strip elements of third
antenna 230 causes polarization in a linear Y direction. In an
illustrative embodiment, first antenna 210 and second antenna 230
may be the only two antennas operating on dielectric substrate
204.
[0043] In an illustrative embodiment, first antenna 210 and second
antenna 220 may operate as a pair of antenna receivers that receive
radio signals simultaneously on a same frequency. The opposing or
orthogonal polarizations of second antenna 220 and third antenna
230 enables high isolation and reduced coupling between second
antenna 220 and third antenna 230. Similarly the opposing or
orthogonal polarization between first antenna 210 and second
antenna 220 enables good isolation. A distance, particularly a
diagonal distance between second antenna 220 and third antenna 230,
may also enable good isolation and reduced coupling
[0044] Turning now to FIG. 3, display 300 of a port network
analyzer illustrates a measurement of return loss at separate feed
ports of antennas in an antenna arrangement according to an
illustrative embodiment of the disclosure. In this depicted
example, display 300 is an example of the return loss measured from
feed ports of antenna elements in antenna arrangement 200 in FIG.
2. It must be noted that display 300 provides measurements based on
an actual antenna system environment, and not based on a simulated
or free space environment.
[0045] Return loss is the ratio of reflected power to incident
power as measured at the feed port of an antenna. Return loss is
expressed in decibels. The X-axis 380 of measured return loss graph
300 provides the frequency of a radio signal in Megahertz. The
Y-axis 390 expresses in decibels (dB) the ratio of reflected and
incident signals to a port. In this illustrative embodiment, an
antenna arrangement, such as antenna arrangement 200 of FIG. 2, is
configured to operate in a 700 MHz range between a frequency of
about 746 MHz at Mkr3 340 and a frequency of about 799 MHz at Mrk1
360.
[0046] As illustrated, display 300 of port network analyzer
illustrates traces of three different signals. Signal trace 1, Trc1
310, illustrates the return loss measured at third feed port 234 of
third antenna 230. Signal trace 3, Trc3 330 illustrates the return
loss measured at second feed port 224 of second antenna 220. Signal
trace 2, Trc2 320, tracks the isolation measured between second
antenna 220 and third antenna 230 as frequency increases.
[0047] The reflected and incident power signals may be represented
by reflection coefficients known as scattering or S parameters. The
scattering parameters define energy or power of a network in terms
of impedance and admittance. The scattering parameters include
S.sub.11 and S.sub.22. S.sub.11 represents the input reflection
coefficient at a first port. S.sub.22 represents the output
reflection coefficient at a second port. S.sub.11 and S.sub.22
provide an indication of how much power is reflected. S.sub.21
shows the isolation between two antennas within an antenna
arrangement or antenna diversity system
[0048] Measured return loss display 300 illustrates the scattering
or S parameters of antenna arrangement 200 depicted in FIG. 2.
Measured return loss display 300 illustrates measurements of the
input reflection coefficient, output reflection coefficient, and
reversed transmission coefficient at two different ports of the
antenna arrangement.
[0049] The return loss of antenna arrangement is measured at two
separate antenna ports. In the illustrative embodiment of FIG. 3,
S.sub.22 corresponds to the return loss analyzed and measured at
feed port 3 of third antenna 230, as illustrated by signal trace 1,
Trc1 310. S.sub.11 corresponds to the return loss analyzed at feed
port 2 of second antenna 220 as illustrated by signal trace 3, Trc3
330.
[0050] S.sub.11, Trc3 330, and S.sub.22,Trc1 310, measure the
coupling and reflection of the third and second antenna,
respectively. The value of the isolation is illustrated by S.sub.21
trace 2, Trc2 320. Within the 700 band resonant frequency, the
isolation may be optimum at Mkr4 350 at a frequency of about 752
MHZ with an isolation of about -19 decibels (dB). An isolation
value within a range of between 15 and 20 decibels is considered
optimum within the 700 MegaHertz frequency range.
[0051] Turning now to FIG. 4, a three-dimensional view of a
normalized radiation pattern 400 measured from at least two ports
of the antenna array is depicted according to an illustrative
embodiment of the system. In the illustrative embodiment,
normalized radiation pattern 400 is illustrated by a port 1 view
410 as measured from second feed port 224 of second antenna 220 and
a port 2 view 420 as measured from third feed port 234 of third
antenna 230 as illustrated in FIG. 2. It must be noted that
radiation pattern 400 provides measurements based on an actual
antenna system environment, and not based on a simulated or free
space environment.
[0052] Radiation pattern 400 illustrates a three dimensional view
of the minimum and maximum radiated power or gain measured at a
large distance from the antenna. The large distance is about
2 D 2 .lamda. , ##EQU00004##
where D is the largest dimension of the antenna and .lamda. is the
wavelength of the frequency. In this illustrative embodiment, the
port 1 410 pattern and the port 2 420 pattern illustrates a dipole
radiation pattern that shows a relative distribution of radiation
power in a range 402 that spans from -21.00 dB to -5.83 dB.
[0053] Port 1 410 pattern and port 2 420 pattern illustrates
radiation patterns that are directional. Directional radiation
patterns radiate signals of high power or gain in a specific
direction. In this embodiment, the maximum radiated power, as
illustrated, is about -21 dB. The directional radiation patterns of
port 1 410 and port 2 420 exemplify or illustrate pattern diversity
as the radiation pattern of port 1 410 differs from the radiation
pattern of port 2 420.
[0054] FIG. 5 illustrates a plot of the antenna efficiency measured
at a port of the antenna array system illustrated in FIG. 1. Plot
500 measures frequency in units of Megahertz (MHz) on the X-axis
580. On the Y-axis 590, a measurement of efficiency is illustrated.
Efficiency is a measure of the percentage of power radiated to the
total power accepted at a port of an antenna. In this illustrative
embodiment, plot 500 illustrates the efficiency measured at a port,
such as port 1 410 of FIG. 4 of the antenna arrangement. It must be
noted that plot 500 provides measurements based on an actual
antenna system environment, instead of a simulated or free space
environment.
[0055] Within any frequency range, it is optimum to have the power
that is radiated be as large as possible. In the illustrative
embodiment of plot 500, the frequency range of interest is around
745 MHz 510 to 787 MHz 530. The maximum radiation power or
efficiency is achieved at around 755 MHz 520 at fifty percent
(50%).
[0056] Referring now to FIG. 6, a block diagram of mobile
communication device 600 is illustrated according to an
illustrative embodiment of the disclosure. Mobile communication
device 600 may be a mobile wireless communication device, such as a
mobile cellular device, herein referred to as a mobile device that
may function as a Smartphone, which may be configured according to
an information technology (IT) policy. Mobile communication device
600 may be configured to an antenna arrangement such as antenna
arrangement 102 depicted in FIG. 1.
[0057] Mobile communication device 600 includes communication
elements in communication subsystem 622 that may be configured to
operate with a plurality of antennas on a dielectric substrate such
as dielectric substrate 104 of FIG. 1. Antenna system 624 may be
configured to support multiple input multiple output technology.
Antenna system 624 may include a plurality of antennas for
simultaneous or individual radio frequency signal
transmissions.
[0058] The term information technology, in general, refers to a
collection of information technology rules, in which the
information technology policy rules may be defined as being either
grouped or non-grouped and global or per user. The terms grouped,
non-grouped, global, and per-user are defined further below.
Examples of applicable communication devices include pagers, mobile
cellular phones, cellular smart-phones, wireless organizers,
personal digital assistants, computers, laptops, handheld wireless
communication devices, wirelessly enabled notebook computers and
such other communication devices.
[0059] The mobile device is a two-way communication device with
advanced data communication capabilities including the capability
to communicate with other mobile devices, computer systems, and
assistants through a network of transceivers. In FIG. 6, the mobile
device includes a number of components such as main processor 634
that controls the overall operation of user equipment 600.
Communication functions are performed through communication
subsystem 622. Communication subsystem 622 receives messages from
and sends messages across wireless link 650 to wireless network
626.
[0060] Communications subsystem 622 provides for communication
between the mobile device 600 and different systems or devices such
as antenna system 624, without the use of the wireless network 626.
For example, communications subsystem 622 may include an infrared
device and associated circuits and components for short-range
communication. Examples of short-range communication standards
include standards developed by the Infrared Data Association
(IrDA), Bluetooth, and the 802.11 family of standards developed by
the Institute of Electrical and Electronics Engineers (IEEE). Short
range communications may include, for example, without limitation,
radio frequency signals within a 2.4 GHz band or a 5.8 GHz
band.
[0061] In this illustrative embodiment of the mobile device, the
communication subsystem 622 is configured in accordance with the
Global System for Mobile Communication (GSM) and General Packet
Radio Services (GPRS) standards. The GSM/GPRS wireless network is
used worldwide and it is expected that these standards will be
superseded eventually by, for example, without limitation, Evolved
Enhanced Data GSM Environment (EEDGE), Universal Mobile
Telecommunications Service (UMTS), High Speed Packet Access (HSPA),
Long Term Evolution (LTE), and other standards applicable to
multiple input multiple output technology. New standards are still
being defined, but it is believed that they will have similarities
to the network behavior described herein, and it will also be
understood by persons skilled in the art, that the embodiments
described herein are intended to use any other suitable standards
that are developed in the future.
[0062] The wireless link 650 connecting the communication subsystem
with wireless network 626 represents one or more different radio
frequency (RF) channels, operating according to defined protocols
specified for GSM/GPRS communications. With newer network
protocols, these channels are capable of supporting both circuit
switched voice communications and packet switched data
communications. Antenna arrangements, such as antenna arrangement
204 of FIG. 2, are implemented by antenna system 624 of
communication subsystem 622. Antenna arrangement 204 is implemented
between network 626 and main processor 634 and enables the mobile
communication device to have a higher data rate and a higher
throughput based on high correlation and isolation.
[0063] Although the wireless network 626 associated with mobile
device 600 may be a GSM/GPRS/EDGE wireless network in one
illustrative implementation, other wireless networks may also be
associated with the mobile device 600 in variant implementations.
Examples of these networks include, but are not limited to, Code
Division Multiple Access (CDMA) or CDMA2000 networks, GSM/GPRS/EDGE
networks (as mentioned above), third-generation (3G) networks such
as UMTS and HSPA, and also future fourth-generation (4G) networks
such as LTE and Worldwide Interoperability for Microwave Access
(WiMax).
[0064] The main processor 634 also interacts with additional
subsystems such as Random Access Memory (RAM) 620, a flash memory
618, a display 616, an auxiliary input/output (I/)O) 638 subsystem,
a data port 640, a keyboard 642, a speaker 644, a microphone 646,
and other device subsystems 636.
[0065] Some of the subsystems of the mobile device 600 perform
communication-related functions, whereas other subsystems may
provide "resident" or on-device functions. By way of example, the
display 616 and the keyboard 642 may be used for both
communication-related functions, such as entering a text message
for transmission over the network 626, and device-resident
functions such as a calculator or task list.
[0066] The mobile device 600 can send and receive communication
signals over the wireless network 626 after required network
registration or activation procedures have been completed. Network
access is associated with a subscriber or user of the mobile device
600. To identify a subscriber, the mobile device 600 requires a
Subscriber Identity Module or a Removable User Identity Module,
SIM/RUIM module 614, to be inserted into a SIM/RUIM interface 628
in order to communicate with a network. The SIM/RUIM module 614 is
one type of a conventional "smart card" that can be used to
identify a subscriber of the mobile device 600 and to personalize
the mobile device 600, among other things. Without the SIM/RUIM
module 614, the mobile device 600 is not fully operational for
communication with the wireless network 626.
[0067] By inserting the SIM/RUIM module 614 into the SIM/RUIM
interface 628, a subscriber can access all subscribed services.
Services may include: web browsing and messaging such as e-mail,
voice mail, Short Message Service (SMS), and Multimedia Messaging
Services (MMS). More advanced services may include: point of sale,
field service and sales force automation. The SIM/RUIM module 614
includes a processor and memory for storing information. Once the
SIM/RUIM module 614 is inserted into the SIM/RUIM interface 628, it
is coupled to the main processor 634. In order to identify the
subscriber, the SIM/RUIM module 614 can include some user
parameters such as an International Mobile Subscriber Identity
(IMSI).
[0068] An advantage of using the SIM/RUIM module 614 is that a
subscriber is not necessarily bound by any single physical mobile
device. The SIM/RUIM module 614 may store additional subscriber
information for a mobile device as well, including datebook (or
calendar) information and recent call information. Alternatively,
user identification information can also be programmed into the
flash memory 618. The mobile device 600 is a battery-powered device
and includes a battery interface 630 for receiving one or more
rechargeable batteries 632. In at least some embodiments, the
battery 632 can be a smart battery with an embedded microprocessor.
The battery interface 630 is coupled to a regulator (not shown),
which assists the battery 632 in providing power V+ to the mobile
device 600. Although current technology makes use of a battery,
future technologies such as micro fuel cells may provide the power
to the mobile device 600.
[0069] The mobile device 600 also includes an operating system 602
and software components 604 to 612 which are described in more
detail below. The operating system 602 and the software components
604 to 612 that are executed by the main processor 634 are
typically stored in a persistent store such as the flash memory
618, which may alternatively be a read-only memory (ROM) or similar
storage element (not shown). Those skilled in the art will
appreciate that portions of the operating system 634 and the
software components 604 to 612, such as specific device
applications, or parts thereof, may be temporarily loaded into a
volatile store such as the RAM 620. Other software components can
also be included, as is well known to those skilled in the art.
[0070] The software applications can further include a device state
module 606, a Personal Information Manager (PIM) 608 and other
suitable modules (not shown). The device state module 606 provides
persistence which means that the device state module 606 ensures
that important device data is stored in persistent memory, such as
the flash memory 618, so that the data is not lost when the mobile
device 600 is turned off or loses power.
[0071] The PIM 608 includes functionality for organizing and
managing data items of interest to the user, such as, but not
limited to, e-mail, contacts, calendar events, voice mails,
appointments, and task items. A PIM application has the ability to
send and receive data items via the wireless network 626
[0072] The mobile device 600 also includes a connect module 610,
and an information technology (IT) policy module 612. The connect
module 610 implements the communication protocols that are required
for the mobile device 600 to communicate with the wireless
infrastructure and any host system, such as an enterprise system,
with which the mobile device 600 is authorized to interface.
[0073] The connect module 610 includes a set of application
programming interfaces (APIs) that can be integrated with the
mobile device 600 to allow the mobile device 600 to use any number
of services associated with the enterprise system. The connect
module 610 allows the mobile device 600 to establish an end-to-end
secure, authenticated communication pipe with the host system. A
subset of applications for which access is provided by the connect
module 610 can be used to pass IT policy commands from the host
system to the mobile device 600. This can be done in a wireless or
wired manner.
[0074] The IT policy module 612 receives IT policy data that
encodes the IT policy. The IT policy module 612 then ensures that
the IT policy data is authenticated by the mobile device 600. The
IT policy data can then be stored in the flash memory 618 in its
native form. After the IT policy data is stored, a global
notification can be sent by the IT policy module 612 to all of the
applications residing on the mobile device 600. Applications for
which the IT policy may be applicable then respond by reading the
IT policy data to look for IT policy rules that are applicable.
[0075] Other types of software applications can also be installed
on the mobile device 600. These software applications can be third
party applications, which are added after the manufacture of the
mobile device 600. Examples of third party applications include
games, calculators, utilities, and other similar applications know
to one skilled in the art.
[0076] The additional applications can be loaded onto the mobile
device 600 through the wireless network 626, the auxiliary I/O 638
subsystem, the data port 640, the communication subsystem 622, or
any other suitable device subsystem 636. This flexibility in
application installation increases the functionality of the mobile
device 600 and may provide enhanced on-device functions,
communication-related functions, or both.
[0077] The data port 640 enables a subscriber to set preferences
through an external device or software application and extends the
capabilities of the mobile device 600 by providing for information
or software downloads to the mobile device 600 other than through a
wireless communication network. The alternate download path may,
for example, be used to load an encryption key onto the mobile
device 600 through a direct and thus reliable and trusted
connection to provide secure device communication.
[0078] The data port 640 may be any suitable port that enables data
communication between the mobile device 600 and another computing
device. The data port 640 may be a serial or a parallel port. In
some instances, the data port 640 may be a USB port that includes
data lines for data transfer and a supply line that can provide a
charging current to charge the battery 632 of the mobile device
600.
[0079] In operation, a received signal such as a text message, an
e-mail message, or web page download will be processed by the
communication subsystem 622 and input to the main processor 634.
The main processor 634 will then process the received signal for
output to the display 616 or alternatively to the auxiliary I/O
subsystem 638. A subscriber may also compose data items, such as
e-mail messages, for example, using the keyboard 642 in conjunction
with the display 616 and possibly the auxiliary I/O subsystem 638.
The auxiliary I/O subsystem 638 may include devices such as: a
touch screen, mouse, track ball, infrared fingerprint detector, or
a roller wheel with dynamic button pressing capability. The
keyboard 642 is preferably an alphanumeric keyboard together with
or without a telephone-type keypad. However, other types of
keyboards may also be used. A composed data item may be transmitted
over the wireless network 626 through the communication subsystem
622.
[0080] For voice communications, the overall operation of the
mobile device 600 is substantially similar, except that the
received signals are output to the speaker 644, and signals for
transmission are generated by the microphone 646. Alternative voice
or audio I/O subsystems, such as a voice message recording
subsystem, can also be implemented on the mobile device 600.
Although voice or audio signal output is accomplished primarily
through the speaker 644, the display 616 can also be used to
provide additional information such as the identity of a calling
party, duration of a voice call, or other voice call related
information.
[0081] Turning now to FIG. 7, a wireless communication network 700
implementing the diversity antenna system of FIG. 1 according to an
embodiment of the disclosure is illustrated. Communication system
700 depicts an implementation of wireless mobile communication
devices, such as mobile communication device 600 of FIG. 6,
transmitting radio frequency signals.
[0082] Communication system 700 may include wireless communication
systems that include a plurality of antennas operating within a
single device including but in no way limited to, multiple input
multiple output (MIMO) radio systems, single input single output
(SISO) communication systems, long term evolution (LTE)
communication systems and other such communication systems that may
be recognized by one skilled in the art.
[0083] In the illustrative embodiment, mobile communication device
710 and mobile communication device 750 may include an antenna
arrangement, such as antenna arrangement 102 of FIG. 1. Mobile
communication device 710 may receive a radio frequency signal,
represented mathematically as time varying signal S.sub.N(t) 702,
where N represents any positive integer greater than zero.
[0084] Signal S.sub.N(t) 702 is a time domain signal that may
comprise a plurality of signals. The time domain signals of
S.sub.N(t) 702 are sampled and converted into weighted time domain
signals by a signal processor 720 using a processing algorithm. The
weighted time domain signals include, without limitation, weighted
time domain signals, S.sub.1 704A, S.sub.2 706A, and S.sub.N 708A.
The processing algorithm used by signal processor 720 may be any
number of algorithms currently known and recognized by those
skilled in the art.
[0085] The weighted time domain signals are transmitted over
antennas 704A, 706A, and 708A, respectively. Each antenna may be a
separate antenna as represented in antenna arrangement 102 of FIG.
1. For example, in an exemplary embodiment, antenna 704A may be
representative of first antenna 110, antenna 706A may be
representative of second antenna 120, and antenna 708A may be
representative of third antenna 130. The radio frequency signals
are transmitted over radio channel 730 to mobile communication
device 750. Radio channel 730 comprises a plurality of
communication paths.
[0086] Mobile communication device 750 receives frequency domain
signals, such as, without limitation, frequency domain signals
y.sub.1 742A, y.sub.2 744A, and y.sub.N 746A over antennas 742A,
744A, and 746A, respectively. Each antenna may be a separate
antenna as represented in antenna arrangement 102 of FIG. 1. For
example, in an exemplary embodiment, antenna 742A may be
representative of first antenna 110, antenna, 744A may be
representative of second antenna 120, and antenna 746A may be
representative of third antenna 130.
[0087] The frequency domain signals are decoded and transformed by
signal processor 740 to obtain information represented by time
domain signal y.sub.N(t) 748, where N represents any positive
integer greater than zero. The processing algorithm used by signal
processor 740 may be any number of algorithms currently known and
recognized by those skilled in the art. Time domain signal
y.sub.N(t) 748, may comprise a plurality of time domain signals or
samples as would be recognized by one skilled in the art.
[0088] Communication system 700 is not meant to imply physical or
architectural limitations to the manner in which different
advantageous embodiments may be implemented. Other components in
addition to or in place of the ones illustrated may be used. Some
components may be unnecessary in some advantageous embodiments. For
example, the plurality mobile communication devices 710 and 750,
respectively, may include an antenna arrangement, such as antenna
arrangement 102 of FIG. 1 that has a plurality of antennas that are
capable of simultaneously receiving or transmitting radio frequency
signals.
[0089] For example, in the depicted embodiment of FIG. 7, antenna
704A and antenna 706A of mobile communication device 710 may form a
pair of antennas for receiving radio frequency signals at a same
time or substantially at a same time over radio channel 730, while
antenna 708A also transmits signals over radio channel 730.
[0090] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein.
[0091] While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without
departing from the spirit or scope of the present disclosure. The
present examples are to be considered as illustrative and not
restrictive, and the intention is not to be limited to the details
given herein.
[0092] The embodiment or embodiments selected are chosen and
described in order to best explain the principles of the
embodiments, the practical application, and to enable others of
ordinary skill in the art to understand the disclosure for various
embodiments with various modifications as are suited to the
particular use contemplated. For example, the various elements or
components may be combined or integrated in another system or
certain features may be omitted or not implemented.
* * * * *